A holographic optical element comprising at least two sets of regions, the regions of each set being different from the regions of the other set(s) and being interleaved or overlapping with the regions of the other set(s) and being constructed such that light incident on each set of regions is directed to a respective one of a plurality of viewing zones. The holographic optical element is typically incorporated in a display device such as a stereoscopic display device.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A display device comprising: a holographic optical element having at least two sets of hologram regions, the regions of the first set being interleaved or overlapping with adjacent regions of the second set and being constructed such that light incident on each set of regions is diffracted so as to construct a respective one or more of a plurality of real or virtual images of a diffuse light source; and image generating means including a plurality of image elements; wherein the holographic optical element and its hologram regions are disposed and designed such that light having passed through a first set of image elements of the image generating means is diffracted by the first set of hologram regions, and light having passed through a second set of image elements of the image generating means is diffracted by the second set of hologram regions.
2. The display device according to claim 1, wherein: the image generating means includes a liquid crystal array and means to illuminate the liquid crystal array, and each image element includes one or more pixels of the liquid crystal array.
3. The display device according to claim 1, wherein the holographic optical element is spaced from the image generating means.
4. The display device according to claim 1, wherein the holographic optical element lies adjacent the image generating means.
5. The display device according to claim 1, further comprising: means to vary the illumination of the image generating means, whereby viewing zones formed by the real or virtual images are moved.
6. The display device according to claim 1 wherein: the image elements define a left hand and a right hand stereoscopic image, each of which is directed to a respective viewing zone; and the display device provides a stereoscopic image in use.
7. The display device according to claim 1 further comprising: a focusing optic which creates a virtual image of the plurality of image elements and the holographic optical element and forms real images of viewing zones, each image being viewed in use through a respective one of the real images of the viewing zones.
8. The display device according to claim 1, wherein the plurality of images together form a two-dimensional image.
9. The display device according to claim 1 further comprising: a plurality of light sources which illuminate the holographic optical element simultaneously whereby a plurality of viewing positions are provided.
10. The display device according to claim 1, wherein the image generating means comprises a monochrome image generating means whereby color images are displayed on the image generating means.
11. The display device according to claim 1, wherein the image generating means is combined with the holographic optical element arranged such that certain regions of the holographic optical element are associated just with the image elements displaying one color separation and other regions of the holographic optical element are associated just with the image elements displaying other color separations, whereby the wavelengths of light diffracted by each set of regions towards a viewer correspond to the color of the color separation displayed by the image elements associated with the color separation, the whole being arranged so as to display a full color two dimensional or three dimensional image.
12. The display device according to claim 1, wherein each set of regions comprises: an array of regions.
13. The display device according to claim 1, wherein each set of hologram regions comprises: a holographic recording of one or more diffuse light sources in one or more of a plurality of different positions with respect to the holographic optical element.
14. The display device according to claim 1, wherein the holographical optical element is constructed as a substrate guided wave device.
15. The display device according to claim 1 wherein each set of reigions comprises: a holographic recording which has been made using a mask having an array of apertures.
16. The display device according to claim 1, wherein each set of regions diffracts light incident on the holographic optical element to form an image of an array of apertures.
17. The display device according to claim 1, wherein the holographic optical element is a surface relief hologram made by molding or embossing.
18. The display device according to claim 1, wherein the holographic optical element is a volume hologram made in photopolymer, dichromated gelatine or silver halide.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
July 28, 2000
May 15, 2001
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